Interrupter switch for rotary solenoid

ABSTRACT

An interrupter switch is assembled in a rotary solenoid having two cooperating rotary conversion plates, one rotatably mounted and one nonrotatably mounted to develop a rotary motion. The rotary motion is transmitted to a driven shaft through a one-way drive mechanism. The driven shaft carries a detent structure coacting with an index plate to locate shaft positions. The interrupter switch is mounted to the index plate and operated by means of a cam slidably mounted in a window through the index plate and driven by a stud affixed to the rotatably mounted rotary conversion plate.

United States 1 Patent Inventor Robert M. Anderson Xenia, Ohio Appl. No. 52,855 Filed July 7, 1970 Patented Dec. 21, 1971 Assignee Ledex Inc.

' Dayton, Ohio INTERRUPTER SWITCH FOR ROTARY SOLENOID 10 Claims, 8 Drawing Figs.

US. Cl 335/122,

220/153 LA, 200/166 SD Int. Cl 1101b 67/06 Field ofSearch 335/122,

123,138, 140,190, 228; 200/153 LA, 153 V, 166 SD, 172 R; 310/32; 74/126 [56] References Cited UNITED STATES PATENTS 3,249,725 5/1966 Hutt et al 200/153 LA 2,289,736 7/1942 Snavely et al. 200/153 LA 2,501,950 3/1950 Leland 310/32 3,320,822 5/1967 Tatom 74/126 Primary Examiner-Harold Broome Attorney-Dybvig & Dybvig ABSTRACT: An interrupter switch is assembled in a rotary solenoid having two cooperating rotary conversion plates, one rotatably mounted and one nonrotatably mounted to develop a rotary motion. The rotary motion is transmitted to a driven shaft through a one-way drive mechanism. The driven shaft carries a detent structure coacting with an index plate to locate shaft positions. The interrupter switch is mounted to the index plate and operated by means of a cam slidably mounted in a window through the index plate and driven by a stud affixed to the rotatably mounted rotary conversion plate.

PATENTEU 08221 1911 INVENTOR. B06627 M flNDEZSO/V INTERRUPTER SWITCH FOR ROTARY SOLENOID BACKGROUND OF THE INVENTION 1 Field of the Invention The present invention relates to a control mechanism for a self-returning rotary solenoid structure and more particularly to an interrupter switch operated by the solenoid structure which terminates a present stroke of the structure and initiates a new stroke when the structure returns itself to a starting position.

2. Description of the Prior Art Interrupter switches which interrupt a present stroke of a rotary solenoid and then initiate a new stroke upon the return of the rotary solenoid to its starting position are known in the prior art. An example of the prior art can be found in U.S. Pat. No. 2,501,950 issued Mar. 28, I950 to G. H. Leland. The structure illustrated in the aforesaid patent is erected external to the rotary solenoid casing and requires a substantial number of intricately constructed parts.

Advances in the rotary solenoid art displayed particularly in U.S. Pat. No. 3,320,822 issued May 23, 1967 to .l. W. Tatom have led to rotary solenoid constructions to which an externally assembled interrupter switch such as illustrated in the aforementioned U.S. Pat. No. 2,501,950 is no longer adaptable. More particularly, the advances in the prior art disclosed in U.S. Pat. No. 3,320,822 render highly desirable an internally constructed interrupter switch such as disclosed in the present application.

SUMMARY OF THE INVENTION The present invention incorporates an internally assembled interrupter switch into a structure such as disclosed in U.S. Pat. No. 3,320,822. The basic structure of U.S. Pat. No. 3,320,822 includes a pair of rotary conversion plates one of which is rotatably mounted and the other of which is nonrotatably mounted, a one-way. drive between the rotatably mounted plate and a driven shaft, a detent mechanism carried by the driven shaft and cooperating with an index plate to position the driven shaft. The interrupter switch of the present invention is mounted upon the index plate and operated by means of a cam slidably mounted in a window located in the index plate. The cam is driven by means of a stud fixed to the rotatably mounted conversion plate. Such assembly allows the interrupter switch to be incorporated into the rotary solenoid housing structure in contrast to the externally constructed interrupter switch mechanisms of the prior art.

BRIEF DESCRIPTION OF THE DRAWING In the drawing, FIG. I is an exploded perspective view of a rotary solenoid construction before modification to incorporate the present invention.

FIG. 2 is a perspective view of an index structure modified in accordance with the present invention.

FIG. 3 is a plan view in the direction of the arrows 33 in FIG. 2.

FIG. 4 is an enlarged fragmentary section view taken substantially along the line 4-4 of FIG. 3.

FIG. 5 is a plan view in the direction of the arrows 5-5 in FIG. 2.

FIG. 6 is a perspective view with a portion broken away illustrating a cam element employed in the modified index mechanism of FIGS. 2, 3 and 4.

FIG. 7 is a perspective view of a rotary conversion plate modified in accordance with the present invention.

FIG. 8 is a perspective view of a dust cover modified in accordance with the present invention.

DETAILED DESCRIPTION FIG. 1 of the drawing is an exploded illustration of a commercially available solenoid construction which, as will be later described, is readily modified to incorporate the present invention. To allow a full understanding of the present invention, the commercially available structure of FIG. 1 will be first described in sufficient detail that the modifications employed to incorporate the present invention will be readily apparent.

The solenoid structure of FIG. 1 comprises a casing 10 fastened to a mounting plate 12 which may have any shape suitable to its purpose. For fastening the casing 10 to the mounting plate, the casing has downwardly projecting threaded bolts I4 which pass through apertures 15 suitably located in the mounting plate 12 to be threadedly engaged by internally threaded nuts 16. Washers as shown at 18 provide suitable bearing surfaces for the nuts 16.

Press fitted within the casing 10 is an annular rotary conversion plate 20 having arcuate inclined recesses 22 in the upper surface thereof. The recesses 22 are three in number spaced at l20 intervals about the central axis of the casing 10. One of the three recesses 22 does not appear in FIG. 1 due to the angle at which the perspective illustration of this Figure was produced.

Disposed within the recesses 22 for rolling engagement therewith are ball bearings 24, there being one ball bearing in each of the three recesses 22. The ball bearings 24 are also adapted to roll within inclined arcuate recesses 28 formed in the under surface of an annular rotary conversion plate 26 which is adapted to be received within the upper part of the casing 10 ahd to have rolling contact with the ball bearings 24.

The recesses 22 in the plate 20 are so sloped with respect to the plane of the upper surface of the plate 20 (shown as horizontal) that a ball bearing 24 when placed in one of said recesses will roll downwardly into the recess in the clockwise direction. The recesses 28 are complementarily inclined so that when the plate 26 is assembled over the plate 20 the bases of the recesses 22 and 28 are disposed in generally parallel planes. This allows the ball bearings 24 to be caged between the plates 20 and 26 with the ball bearings 24 lying at the clockwise extremities of the recesses 22 and the counterclockwise extremities of the recesses 28. Such construction allows the plate 26 to be rotated upon the ball bearings 24 in the counterclockwise direction to a position where the ball bearings 24 are lodged in the counterclockwise extremities of the recesses 22 and also in the clockwise extremities of the recesses 28. In this latter position the plate 26 is elevated above the plate 20 and when pressed downwardly toward the plate 20 will develop a strong clockwise torque resulting from the tendency of the ball bearings 24 to roll toward the deeper ends of the recesses 22 and 28. As well known to those skilled in the art, the recesses 22 and 28 are not so deep in the plates 20 and 26 at their deepest ends that these plates can engage in facial contact. Also, the recesses 22 and 28 are not so shallow at their shallowest ends that the ball bearings 24 can roll freely out of any of the recesses.

Assembled above the plate 26 and still within the casing 10 is a split spring-ring 30. The spring-ring 30 has a relaxed diameter slightly larger than the diameter of the interior wall 33 of the casing 10. Accordingly the spring-ring 30 must be slightly compressed for insertion within the wall 33 and when inserted expands radially to frictionally engage the wall 33. The spring-ring 30 has upturned ears 32 which anchor springs 34, there being three equally spaced ears 32 and one spring 34 for each ear 32.

The interior ends of the springs 34 as viewed in FIG. I are hooked into annular grooves 38 located in upstanding studs 36 disposed at equal intervals in the upper surface of the previously described plate 26. The spring-ring 30 is so located that the springs 34 engaged to the studs 36 exert a counterclockwise torque on the plate 26 and thereby hold the plate 26 at its elevated position in which the balls are lodged in the shallow ends of the recesses 22 and 28.

Disposed in the upper surface of the plate 26 and adjacent the inner periphery thereof is a circular array of upwardly facing teeth 40. The teeth 40 are adapted to interfit complementary teeth 42 integral with and projecting radially outwardly from an armature 44. The armature 44 is sized to fit within the central opening of the annular plate 26 to allow the radially outwardly projecting teeth 42 to interfit the teeth 40 of the plate 26.

The armature 44 is a ferromagnetic body which is adapted to be magnetically attracted to a ferromagnetic core 45 integrally formed within the casing and which is surrounded by a coil 47 (not shown in detail) disposed under the plate 20. Upon electrical energization of the coil 47 with a direct current, the core 45 develops a strong magnetic field which attracts the armature 44. The pressure thus exerted by the armature 44 against the plate 26 causes the recesses 22 and 28 to coact with the ball bearings 24 in such fashion as to develop a strong clockwise torque in the plate 26. The interfitting teeth 40 and 42 of the plate 26 and armature 44, respectively, couple the armature 44 with the plate 26 so as to transmit this torque to the armature 44.

The springs 34 resist this clockwise torque developed in the plate 26 but upon passage of a sufficient current through the coil 47 the torque developed in the plate 26 is sufficient to overpower the springs 34 whereupon the plate 26 rotates in the clockwise direction until the ball bearings 24 have reached the lower ends of the recesses 22 and 28. When the ball bearings 24 have reached the lower ends of the recesses 22 and 28, rotation of the plate 26 in a clockwise direction will cease for the reason that the recesses 22 and 28 then fully cage the ball bearings 24.

Upon subsequent deenergization of the coil 47, the magnetic field which had attracted the armature 44 collapses and the springs 34 return the plate 26 in the counterclockwise direction, thus returning the ball bearings 24 to the shallow ends of the recesses 22 and 28. Obviously by repeated energization and deenergization of the coil 47, the plate 26 will be repeatedly oscillated clockwise, then counterclockwise, through an angle determined by the circumferential lengths of the recesses 22 and 28. Such oscillating motion of the plate 26 is used to obtain a stepwise unidirectional movement of an output shaft 46.

The shaft 46 is journaled within the core 45, which may have a suitable bearing (not shown) for this purpose. The shaft 46 is retained within the core 45 by means of a retained clip 48 disposed below the casing 10 and seated in an annular groove 51 of the shaft 46. A washer 50 interposed between the clip 48 and the core 45 provides a bearing surface for the clip 48.

Fixedly attached to the shaft 46 is a detent cage 56 having downwardly projecting studs 58 which enter a diametrically disposed groove 59 in the armature 44. The armature 44 is also equipped with a central aperture 57 through which the shaft 46 freely passes.

Sized to fit freely into the interior wall 33 of the casing 10 to a position of rest against the spring-ring 30 is a hollow cylindrical spacer 60. Press fitted within the spacer 60 is a generally annular index plate 61 having circumferentially spaced index lobes 62. The spaced lobes 62 cooperatively produce an undulating interior wall for the index plate 61.

When the device has been assembled so that the studs 58 affixed to the detent cage 56 are disposed in the diametric groove 59 of the armature 44 and the spacer 60 is disposed in its position of rest upon the spring-ring 30, diametrically disposed bores 63 in the detent cage 56 will be disposed in confronting relation to the interior wall of the index plate 61. Each of the bores 63 receives a spring 66 followed by a detent ball 64 and the springs 66 urge the detent balls 64 radially outwardly against the interior wall of the index plate 61.

In a commonly used embodiment of the solenoid structure of FIG. 1, the index plate 61 will be equipped with l2 lobes 62 disposed at 30 intervals about the interior wall of the index plate. correspondingly, the plate 26 will have 12 equally spaced teeth 40 and the armature 44 will be designed with teeth 42 which interflt the 12 teeth of the plate 26. The recesses 22 and 28 are designed to generate a 30 rotation of the plate 26 when the coil 47 is energized.

As a starting position, it can be assumed that the diametrically disposed detent balls 64 associated with the detent cage 56 are lodged in diametrically opposite lobes 62 of the index plate 61 at the time the coil 47 is electrically energized, By means to be later described in detail, the spacer 60 is held in a positive alignment with the plate 20, the alignment being such that whenever the detent balls 64 are lodged in diametrically opposed index lobes 62, the studs 58 associated with the detent cage will support the armature 44 in such rotary position that the teeth 42 thereof interfit the teeth 40 of the plate 26. This interfitting condition requires of course that the springs 34 associated with the spring-ring 30 have biased the plate 26 to a position in which the ball bearings 24 are lodged in the shallow ends of the recesses 22 and 28. Upon electrical energization of the coil 47 the armature 44 will be drawn toward the core 45 and as a result the ball bearings 24 coacting with the recesses 22 and 28 will cause the plate 26 to execute a 30 clockwise stroke. This 30 stroke will be transmitted through the diametric groove 59 in the armature 44 and the studs 58 to the detent cage 56 such that the detent balls 64 are rotated 30 in a clockwise direction so as to move the detent balls 64 to the next adjacent pair of diametrically disposed index lobes 62. Upon a subsequent deenergization of the coil 47, the springs 66 are strong enough to hold the detent cage 56 in its new position as the springs 34 return the plate 26 through a 30 stroke in the counterclockwise direction to its starting position. During this return stroke of the plate 26, the teeth 40 thereof slip under the teeth 42 of the armature 44 which is no longer subject to a magnetic attraction. The teeth 40 and 42 thus function as a one-way drive mechanism.

The result of a single energization of the coil 47 followed by a deenergization thereof is a rotation of the detent cage 56, the armature 44 and the shaft 46 30 in the clockwise direction as viewed in FIG. 1. Upon a second energization of the coil 47 followed by a deenergization thereof, the detent cage 56, shaft 46 and-armature 44 will again be rotated 30 in the clockwise direction. Thus, succeeding energizations of the coil 47 advance the shaft 30 for each energization, the shaft movement being a stepwise unidirectional movement in the clockwise direction. In contrast, the movement of the plate 26 is an oscillatory movement comprising 30 to-and-fro steps. A more detailed description of these movements together with a description of the advantages attending the use of the interfitting teeth 40, 42 can be found in US. Pat. No. 3,320,822 issued to J. W. Tatom and assigned to the assignee of the present application.

To satisfactorily achieve the described movement, it is important that the spacer 60 hold the index plate 61 in a precise rotational alignment with respect to the recesses 22 associated with the plate 20. This is achieved with the aid of a dust cover 68 which telescopes about the upper margin of the spacer 60, The dust cover 68 is equipped with a bearing insert 70 which telescopically receives the shaft 46. The dust cover 68 is also equipped with a radially outwardly projecting flange 72 which moves into close proximity-to the uppermost margin of the casing 10 as the dust cover is moved into position. The dust cover is firmly secured into position by a clamp member 74 which has a lower flange 78 seated in a groove 80 adjacent the upper margin of the casing 10 and also having a flange 76 spaced from the flange 78 so as to receive the flange 72 of the dust cover thereunder. The clamp 74 is equipped with a screw 84 which threadedly engages in a lug 82 to tighten the clamp 74 by reducing the diameter thereof.

While not clearly apparent in the drawing, the flanges 76 and 78 are slightly convergent in the radial outward direction so that as the clamp 74 is tightened by the screw 84 the flange 72 of the dust cover 68 is drawn downwardly toward the casing 10. This downward pressure of the dust cover developed by tightening of the screw 84 acts against the spacer 60 to press this ring against the spring-ring 30. As a result the springring 30 is also pressed downwardly against a shoulder 31 formed within the casing 10. The resultant friction developed between the spacer 60, the spring-ring 30, and the shoulder 31 strongly locks the ring 30 against rotation and also preserves the desired alignment between the index plate 61 and the recesses 22 and the plate 20.

After the assembly is completed in the manner described, the shaft 46 is given a precise axial location with respect to the casing by means of a retainer clip 52 seated in a groove 55 of the shaft 46 and a washer 54 inserted between the bearing 70 and the clip 52.

As indicated in an earlier portion of this specification, the structure of FIG. I is a commercially available structure and has been described in detail to lay a convenient foundation for description of the present invention. A common application for the solenoid structure shown in FIG. 1 resides in the precise stepwise operation of one or more rotary switch ele ments which may be attached to the shaft 46. Such operation can be accomplished, as one example, with the aid of a manual pushbutton switch (not shown) by which an operator can step the shaft 46 through 30 rotational increments by successive depressions of the .pushbutton.

To equip the device as illustrated in FIG. 1 with a selfstepping characteristic, the index plate 61 as shown in FIG. 1

is modified to produce a modified index plate 61a illustrated in FIGS. 2, 3, 4 and 5. The plate 61a retains the same general shape as the original plate 61 except that an arcuate window 86 which extends through an are generally concentric to the axis of the shaft 46 has been cut in the plate 61 in radially outwardly spaced relation to the array of lobes 62 already present in the index plate 61. The curved side margins of the window 86 serve as a guide for a cam member 88 disposed for sliding circumferential movement within the window 86. As best illustrated in FIG. 6 this cam member comprises an oblong plate 89 which is adapted to slide on the upper surface of the index plate 61a, as viewed in FIG. 4, together with a depending skirt 90 which is adapted to slidably engage the margins of the window 86. The skirt 90 defines an oblong pocket 92 underlying the plate 89. It will be noted in FIGS. 5 and 6 that the circumferentially opposite ends of the window 86 are rounded and the circumferentially opposite ends of the skirt 90 are similarly rounded so that the cam member 88 can slide circumferentially within the limits allowed by the window 86 without binding or snagging at the circumferentially opposite ends of the window 86.

The cam member 88 is adapted to follow, with a lost motion to be described, the movements of a modified stud affixed to the plate 26 and which functions to anchor one of the springs 34. The stud which the cam member 88 will follow is longer than the studs 36 illustrated in' FIG. 1 and has been identified by the reference number 94 in FIG. 7. It will be noted that the stud 94 is equipped with anannular groove 95 for anchoring a spring 34 at substantially the same vertical elevation as the grooves 38 described with reference to FIG. 1, but that the portion of the stud 94 projecting above the groove 95 is substantially longer than appears for the remaining studs 36 affixed to the plate 26.

The vertical height of the stud 94 is sufficient that the stud 94 can fit freely into the pocket 92 of the cam member 88.

The pocket 92 is correspondingly sized to slidably receive the stud 94 and the arcuate ends of the skirt 90 are likewise sized to interfit the circular shape of the stud 94 without developing a binding or snagging condition between the stud 94 and the skirt 90. The stud 94 is thus operatively connected to the cam member 88 and functions as an operator for moving the cam member 88.

The design of the skirt 90 is such that the stud 94 can have approximately 24 free travel within the confines of the skirt 90. Recalling however that the stud 94 will execute an approximate 30 stroke, it follows that the stud 94 in executing its 30 clockwise stroke will carry the cam member 88 in the clockwise direction throughout its last 6 of movement. The window 86 is sized to accommodate this 6 movement of the cam member 88 and, as is common practice, is somewhat oversized as a tolerance measure to prevent any substantial impact between the stud 94 and the margin of the window 86 through the thickness of the skirt 90.

By an inspection of FIG. 5, it can be noted that the clockwise end of the window 86 is located in approximate radial alignment with one of the lobes 62 in the index plate 61a. This location results from the arbitrarily designed relationships between the detent cage 56, the studs 58 projecting downwardly therefrom, the diametric groove 59 in the armature 44, and the positions of the teeth 42 with respect to this groove. Except to accommodate these arbitrarily designed relationships, the circumferential location of the window 86 in the index plate 61a and the selection as to which one of the spring anchoring studs 36 will be replaced by the modified stud 94 is unimportant. Thus, the index plate 61a has essentially 360 of rotational freedom with respect to the casing 10 and can be rotated to whatever position is required to position the stud 94 within the pocket 92 and in such location that the full 30 stroke of the stud 94 can be accommodated within the window 86.

Mounted upon the upper face of the index plate 610, as viewed in FIG. 4, is an interrupter switch blade 96. One end of the blade 96 is fastened to an insulating block 102 by means of tubular rivets 98 and 100 which are electrically isolated from the index plate 61a by means of insulating sleeves I04.

Attached to the free end of this cantilever mounted blade 96 is a conductive contact 106 adapted to make engagement with a mating contact 108 which is the headed end of a generally solid rivet 112. The rivet 112 is electrically isolated from the index plate 61a by means of an insulating grommet 114. In securing the rivet 112 and grommet 114 to the index plate 61a, a terminal strap is entrapped under the headed end of the rivet 112 for purposes of an electrical connection to be described.

As best appears in FIG. 3, the switch blade 96 has a curvature concentric with the outer periphery of the index plate 61a. It will also be noted in FIG. 3 that the switch blade 96 is positioned so as to overlie the window 86 and the cam member 88 which is slidably mounted in the window 86.

As can be seen in FIG. 4, the switch blade 96 has a V- shaped cam follower I20 therein at a position intermediate the contact 106 and the rivet 100. Formed integrally with the cam member 88 and projecting above its plate 89 as viewed in FIG. 4 is a shelf 116 and a beveled cam surface 118 descending from one margin of the shelf 116 to the upper surface of the plate 89. In reference to FIG. 3 it can be observed that the clockwise stroke of the plate 26 and the stud 94 mounted thereon will result in a movement of the member 88 in the direction of the contact 106 and thus, with reference to FIG. 4, will result in a movement of the member 88 to the right as viewed in FIG. 4. Such movement will cause the cam surface 118 to initially engage the cam follower 120 in the blade 96 and, with continuing movement of the member 88, will cause the shelf 116 to slide under the cam follower 120. This movement results in an upward pivotal motion of the blade 96 which causes the contact 106 to disengage the contact 108. It was previously described that the movement available to the member 88 is substantially 6 and therefore the movement by which the cam surface 118 engages the cam follower 120 and thereafter the shelf 116 slides under the cam follower 120 occurs in a 6 movement of the cam member 88 about the axis for the shaft 46.

To be assured that the switch blade 96 will have a crisp and positive action, an arcuate stiffener rib 122 is pressed upwardly from the body of the blade 96 between the cam follower 120 and the rivet I00. Absent the stiffener rib 122, the bending of the blade 96 caused by movement of the cam surface 118 under the cam follower 120 would be distributed over a substantial length of the blade 96 and the force that would return the contact 106 to the contact 108 as the solenoid device resets after deenergization of its coil 47 would be proportionately small. More importantly, the blade 96 will tend to be flimsy along its length and contact chatter upon return of the contact 106 to the contact 108 and also in environments subject to external vibration will become a problem. Conceivably, the possibility of contact chatter might have been reduced by shortening the overall length of the switch blade 96 between the rivet 100 and the cam follower 120. However, this would then have required a sharper bend in the blade 96 as this blade is positioned by the cam surface 118. As well understood by those skilled in the art, this sharper bending of the blade 96 would increase the fatigue occurring in the metal of the blade 96 and thereby shorten the useful life of the blade. The stiffener rib 122 offers a desirable compromise in that it allows the length of the blade 96 to be increased so as to reduce flexure and fatigue and at the same time maintains a crisp and positive pressure between the contacts 106 and 108 when the cam member 88 is in the position illustrated in FIG. 4.

From the foregoing description it can be recognized that when the coil 47 is energized the cam member 88 will, in the final 6 of motion executed by the stud 94, operate to separate the contacts 106 and 108. Preferably, the cam surface 118 is so located with respect to the cam follower 120 that an actual separation of the contact 106 and 108 will not occur until the last approximately 4 of travel of the cam member 88 and then, when the cam member 88 has reached the end of its clockwise travel, the cam follower 120 will be lodged on top the shelf 116 so as to assure a positive separation of the contacts 106 and 108. The object is to delay a separation of the contacts 106 and 108 until the armature 44 has sufficient rotary momentum to carry itself and the plate 26 through a full 30 stroke despite the fact that the coil 47 will be deenergized before the full 30 stroke has actually been accomplished. It is likewise important that the shelf 116 will remain under the cam follower 120 as the springs 34 return the plate 26 in the counterclockwise direction so as to delay closure of the contacts 106 and 108 until the 30 return stroke is nearly complete. In the present design this is assured by allowing a 24 return of the stud 94 as the stud traverses the pocket 92 followed by an additional few degrees of movement of the cam member 88 required to move the cam follower 120 off the shelf 116 and down the cam surface 118.

From the foregoing discussion it is evident that the contacts 106 and 108 are designed to be placed in series with the energy source for the coil 47. Thus, FIG. 1 shows power supply terminals 130 and 131 for supplying power to the solenoid coil 47. FIG. 2 illustrates a conductive wire 124 soldered to the aforementioned terminal strap 110. FIG. 2 also illustrates a conductive wire 126 attached to a terminal 125 which is an extension of the blade 96 beyond the rivet 98. The wires 124 and l26are permitted to exit from the solenoid structure illustrated in FIG. 1 through a grommet 128 provided for this purpose in a modified dust cover 68a illustrated in FIG. 8. Either one of the wires 124 and 126 can then be connected to either one of the terminals 130 and 131 whereupon power for operation of the solenoid is applied to the other one of the wires 124 and 126 and also the other one of the terminals 130 and 131. This completes the circuit by which power is supplied to the coil 47 through the contacts 106 and 108 of the interrupter switch and thus subject to the control of the interrupter switch. I

It can thus be seen that by a modification of the commercially available solenoid device described with reference to FIG. 1 which did not change the size or shape of the solenoid device, an interrupter switch has been included in the solenoid device. The only changes in the design of the device required for accommodation of the interrupter switch are those changes described with reference to the index plate 61, one of the spring retaining studs 36 and the dust cover 68.

Having thus described my invention, I claim:

1. A device of the class described comprising, in combination, an electromagnet, a casing for said electromagnet, an armature attracted to said electromagnet upon energization thereof, rotary conversion means comprising a first member nonrotatable with respect to said casing and a second member rotatable with respect to said casing, coupler means to couple said armature with one of said members, said rotary conversion means responding to attraction of said armature by said electromagnet to impart limited rotation in a first direction to said second member, switch means for connection in circuit with said electromagnet, said switch means including a supporting plate nonrotatably mounted to said casing, said switch means including normally closed first and second contact members and means mounting said contact members to said supporting plate, the means mounting one of said contact members being movable and having a cam follower, said plate having a window therethrough, cam means disposed in said window and mounted for movement on said plate, operator means operatively connected to said second member and said cam means to move said cam means on said plate and against said cam follower to open said contacts upon movement of said second member in said first direction.

2. The device of claim 1 including yielding means acting between said second member and said casing to resist movement of said second member in said first direction, said yielding means returning said second member in a second direction to its initial position upon deenergization of said electromagnet, said operator means having lost motion with respect to said cam means whereby movement of said cam away from said cam follower upon return of said second member is delayed by said lost motion.

3. The device of claim 2 wherein said cam member has a skirt defining a pocket to receive a portion of said operator means, said skirt being oversized with respect to said portion to provide said lost motion.

4. The device of claim 3 wherein said portion is disposed eccentric to the axis of the rotation of said second member and wherein said window has a margin extending concentric to the axis of rotation of said second member, said margin guiding said cam means through an arc concentric to the axis of rotation of said second member.

5. The device of claim 1 wherein said supporting plate is an index plate, said device including a driven shaft coaxial to the axis of rotation of said second member, said shaft having a detent cage affixed thereto, means coupling said detent cage to said armature, a detent element supported by said detent cage and operatively engaging said index plate.

6. The device of claim 5 wherein said index plate has a plurality of detent lobes arranged in circular array about said detent cage and said detent element is adapted to engage in said detent lobes.

7. The device of claim 5 wherein said rotary conversion means is disposed between said electromagnet and one face of said index plate, wherein said switch is mounted to an opposite face of said index plate and wherein said operator means projects into said window to engage said cam means.

8. The device of claim 1 wherein the means mounting said one contact member includes a resilient blade having said cam follower and cantilever mounted to said supporting plate, said blade overlying said window, said operator means adapted to interpose said cam means between said cam follower and said supporting plate upon movement of said second member in said first, direction, said cam means having a cam surface adapted to displace said cam follower outwardly from said plate to open said contacts upon interposition of said cam means between said cam follower and said supporting plate.

9. The combination of claim 8 wherein said cam follower is spaced from the cantilever mounted end of said blade and said blade has a stiffener rib in the space between said cam follower and said cantilever mounted end of said blade.

10. A switch device and an operator therefore comprising, in combination, a plate having a window therethrough, an elongate switch blade cantilever supported at one end thereof to said plate and disposed above one face of said plate, said blade overlying said window, a first contact mounted to said plate, said blade having a second contact adjacent the unsupported end thereof and normally engaging said first contact, said switch blade having a cam follower projecting toward said one face, said cam follower disposed intermediate said second contact and the cantilever mounted end of said blade, said blade having a stiffener rib in the body thereof intermediate the cantilever mounted end thereof and said cam follower, cam means slidably mounted in said window and adapted by sliding movement thereof in said window to be interposed 

1. A device of the class described comprising, in combination, an electromagnet, a casing for said electromagnet, an armature attracted to said electromagnet upon energization thereof, rotary conversion means comprising a first member nonrotatable with respect to said casing and a second member rotatable with respect to said casing, coupler means to couple said armature with one of said members, said rotary conversion means responding to attraction of said armature by said electromagnet to impart limited rotation in a first direction to said second member, switch means for connection in circuit with said electromagnet, said switch means including a supporting plate nonrotatably mounted to said casing, said switch means including normally closed first and second contact members and means mounting said contact members to said supporting plate, the means mounting one of said contact members being movable and having a cam follower, said plate having a window therethrough, cam means disposed in said window and mounted for movement on said plate, operator means operatively connected to said second member and said cam means to move said cam means on said plate and against said cam follower to open said contacts upon movement of said second member in said first direction.
 2. The device of claim 1 including yielding means acting between said second member and said casing to resist movement of said second member in said first direction, said yielding means returning said second member in a second direction to its initial position upon deenergization of said electromagnet, said opErator means having lost motion with respect to said cam means whereby movement of said cam away from said cam follower upon return of said second member is delayed by said lost motion.
 3. The device of claim 2 wherein said cam member has a skirt defining a pocket to receive a portion of said operator means, said skirt being oversized with respect to said portion to provide said lost motion.
 4. The device of claim 3 wherein said portion is disposed eccentric to the axis of the rotation of said second member and wherein said window has a margin extending concentric to the axis of rotation of said second member, said margin guiding said cam means through an arc concentric to the axis of rotation of said second member.
 5. The device of claim 1 wherein said supporting plate is an index plate, said device including a driven shaft coaxial to the axis of rotation of said second member, said shaft having a detent cage affixed thereto, means coupling said detent cage to said armature, a detent element supported by said detent cage and operatively engaging said index plate.
 6. The device of claim 5 wherein said index plate has a plurality of detent lobes arranged in circular array about said detent cage and said detent element is adapted to engage in said detent lobes.
 7. The device of claim 5 wherein said rotary conversion means is disposed between said electromagnet and one face of said index plate, wherein said switch is mounted to an opposite face of said index plate and wherein said operator means projects into said window to engage said cam means.
 8. The device of claim 1 wherein the means mounting said one contact member includes a resilient blade having said cam follower and cantilever mounted to said supporting plate, said blade overlying said window, said operator means adapted to interpose said cam means between said cam follower and said supporting plate upon movement of said second member in said first direction, said cam means having a cam surface adapted to displace said cam follower outwardly from said plate to open said contacts upon interposition of said cam means between said cam follower and said supporting plate.
 9. The combination of claim 8 wherein said cam follower is spaced from the cantilever mounted end of said blade and said blade has a stiffener rib in the space between said cam follower and said cantilever mounted end of said blade.
 10. A switch device and an operator therefore comprising, in combination, a plate having a window therethrough, an elongate switch blade cantilever supported at one end thereof to said plate and disposed above one face of said plate, said blade overlying said window, a first contact mounted to said plate, said blade having a second contact adjacent the unsupported end thereof and normally engaging said first contact, said switch blade having a cam follower projecting toward said one face, said cam follower disposed intermediate said second contact and the cantilever mounted end of said blade, said blade having a stiffener rib in the body thereof intermediate the cantilever mounted end thereof and said cam follower, cam means slidably mounted in said window and adapted by sliding movement thereof in said window to be interposed between said cam follower and said one face, said cam means having a cam surface adapted to displace said cam follower outwardly from said one face to disengage said first and second contacts upon interposition of said cam means between said cam follower and said one face. 